Electric utility company Endesa and Gas Natural Fenosa have successfully completed Spain’s first blockchain energy trade transaction. The companies completed a deal for a total of 5.95 gigawatt hours (GWh) of natural gas.

Endesa is the largest electric utility company in Spain. The company has 10 million customers in Spain, with domestic annual generation of over 97,600 GWh from nuclear, fossil-fueled, hydroelectric, and renewable resource power plants. Gas Natural Fenosa is a natural gas and electrical energy utilities company which operates primarily in Spain.

The transaction has been facilitated by Enerchain, a joint initiative which involves 39 major European energy companies. Developed by German software firm Ponton, Enerchain was officially launched in May 2017. It is the first decentralized energy trading platform involving physical delivery. The platform can be used to trade gas and electricity for any area in Europe and any supply period, from the very short-term to annual baseload transactions.

Endesa said demo transactions have already taken place during the past year. On Tuesday, at the E-World trade fair, which is being held in Essen, Germany, the first real trade transaction has been closed.

“Through this project, we are leveraging on cutting-edge solutions to build a trading platform that can lower energy supply costs, while creating value for customers, in line with the Enel Group’s Open Innovation philosophy,” said Javier Alonso, Director of Trading at Endesa.

Italian utility company Enel, Endesa’s parent company, is also involved in the Enerchain initiative. Last year, Enel and E. ON traded electricity for the first time using the blockchain platform.

Gas Natural Fenosa was also pleased with the operation’s success. “With this transaction, Gas Natural Fenosa shows its commitment to innovation,” said David Guerra, Director of Trading at Gas Natural Fenosa, and Susana Calvo, the company’s deputy director of Emerging Businesses. “Blockchain technology, though it still has to overcome some relevant challenges, has the potential to transform many areas in which energy companies are active, with major benefits for our customers, both in terms of price and services.”

Energy companies has been actively collaborating with blockchain firms to explore the potential of the technology in the sector.

Last month, BTL Group announced the second phase of its European energy trading project. Under the project, four oil and gas companies and five energy traders propose to participate in BTL’s Interbit blockchain platform. The project participants include Eni Trading & Shipping, Total, Gazprom Marketing & Trading Limited, Mercuria, Vattenfall, Petroineos, and Freepoint. The aim is to deliver gas-trading reconciliation through to settlement and delivery of trades.